[Stoves] Effects of biomass pellet composition on the thermal and emissions performances of a TLUD cooking stove
Ronal W. Larson
rongretlarson at comcast.net
Mon Aug 20 09:09:16 CDT 2018
Paul, Crispin and List:
See inserts.
> On Aug 19, 2018, at 3:27 PM, Anderson, Paul <psanders at ilstu.edu> wrote:
>
> Crispin and Ron,
>
> I will agree and disagree a little with each of you.
[RWL1: I'm not sure what you are disagreeing with me about. I agree on all three of your points below.
Crispin has responded negatively on all your points (as he did earlier for my response), so I will respond separately ASAP to his new multiple points. I only respond below briefly on his comments back to me - which you kindly have repeated below.
I have a time problem this morning, so say here that I hope Crispin will check all of this with the first author. I believe he is letting that person especially down.
More responses below.
>
> 1. The physical characteristics of the stove are highly important because TLUD stoves can be made in so many ways. Therefore, the name of that specific stove is important if we are to be able to replicate or improve or comment about the stove.
>
> 2. Does this TLUD stove make char? If it is a TLUD stove, it DOES make char. But the user might choose to consume the char inside the stove by continuing to cook after the pyrolytic front reaches the bottom of the batch of fuel. If that is done, that needs to be clearly indicated in the report. And such cooking with char is unlikely to be at the typical high power used for Chinese cooking, so is something else different? Unanswered questions mean that a more complete report would have helped.
>
> 3. ... energy density >21 MJ/kg... is indeed unusual. Expecting about 16 MJ/kg, means 5/16 = 30% increase. Such a difference should have received a sentence or two of comment. Now we are just guessing about possible oil content in peanut shells or some other reason.
>
> I am glad that the research was done and that the report was published. If Crispin knows the researcher(s) or their host institution, perhaps we might get some clarification.
[RWL2: Crispin's response a few hours ago to this last sentence might not have been understood by some. Crispin IS a co-author. Quite possible that he never read it - being given a thank-you cite.
>
> Paul (I am on my way to the US Biochar Initiative conference from Monday through Thursday.)
[RWL3: I paid to go but had to bow out. Please keep us informed of things that are stove related.
More below
>
> Doc / Dr TLUD / Paul S. Anderson, PhD
> Exec. Dir. of Juntos Energy Solutions NFP
> Email: psanders at ilstu.edu Skype: paultlud
> Phone: Office: 309-452-7072 Mobile: 309-531-4434
>
>> -----Original Message-----
>> From: Stoves <stoves-bounces at lists.bioenergylists.org> On Behalf Of Crispin
>> Pemberton-Pigott
>> Sent: Saturday, August 18, 2018 10:30 PM
>> To: 'Stoves (stoves at lists.bioenergylists.org)'
>> <stoves at lists.bioenergylists.org>
>> Subject: Re: [Stoves] Effects of biomass pellet composition on the thermal and
>> emissions performances of a TLUD cooking stove
>>
>> Dear Ron
>>
>> Taken in order:
>>
>>> I was disappointed in this article.
>>
>> I am disappointed that you are disappointed. These fuels are proposed as
>> substitutes for wood to the extent that are available. Very little work has been
>> done investigating emissions from any small stoves. Or at all.
[RWL4: This is a strange comment. I like the work of Jim Jetter in this regard. On this list, Kirk Harris has reported a lot. I liked the doctoral thesis of Jessica Tryner (CSU) on TLUDs specifically. There are emission reports on small stoves in all 14 of the ETHOS conferences (see http://www.ethoscon.com/proceedings-archive/ <http://www.ethoscon.com/proceedings-archive/>).
I agree there could have been much more- but at least hundreds exist. This is a long way from being the first.
>>
>>> 1. A TLUD with zero measurement of char production - makes no sense.
>>
>> That depends on the culture. Apparently in your culture they measure char.
>> Why do you think there was any char at all? The purpose of the stove is to burn
>> the fuel and cook, not produce char..
[RWL5. Nope. In this paper the intent was to study 3 specific types of fuel in apparently identical pellets. No cooking involved. And a cooking test procedure was and is inappropriate. For one thing, the tests would have been conducted more than once each.
>>
>>> 2. Said to be a popular stove. I find it inconceivable that users routinely do
>> what is done here - count all char as waste.
>>
>> They don't routinely do anything with any residual char. Who says there was
>> wasted char? Lots of people don't want char. They want cooking with as little
>> fuel as possible because they have to buy it.
[RWL6. If a stove that makes char is reported to have 15% efficiency, I think most on this list would like to know more on the char production. Even more so when the result is so out of balance with any other ever.
>>
>>> The name of the stove is not given.
>>
>> The name is irrelevant.
[RWL7. I asked in hope of finding out both why the performance was so poor - and if that could have caused the strange result.
>>
>>> This should be about a Tier 0 or Tier 1 stove as listed by an efficiency
>> computation of about 15%.
>>
>> Some people are worried about fuel efficiency, some about emission, some
>> about cooking power. In China most cooking is doing at high power. Most
>> complaints about stoves are about the lack of cooking power.
[RWL8: Again - the tier level or efficiency could have something to do with you report (which would lead to the conclusion peanut shell pellets should be banned).
>>
>>> 3. Mention is made of the importance of density - but no densities are
>> provided.
>>
>> I think that is an omission that could have been filled: first the density of the
>> pellets, and then the bulk density.
[RWL9: Agreed - but I doubt that either density is the cause of this very curious report on peanut shells. I'll bet that if the test is repeated, that either density will be much different from the other two stocks. The test results are very similar, except for the reported efficiency.
>>
>>> There is talk of pellets absorbing water easily.
>>
>> That is an important observation - more important than the density. Some
>> pellets do not absorb water easily.
[RWL10: I raised it because the anomalous result came from the pellets with the highest moisture content (and still having an amazing energy content).
>>
>>> 4. One of the fuels (the one with the highest moisture content) is listed as
>> having an energy density >21 MJ/kg; I've never seen one that high.
>>
>> So you have learned something informative about peanut shell pellets. The
>> energy density is reported AD (After drying). That is indeed the energy
>> content. Perhaps there is vegetable oil in it.
[RWL11: The report on energy content should ALWAYS be on the pellets as being used - not as if they were dried.
Perhaps there is vegetable oil in it? I look forward to hearing if that is the case. The other figures in the paper show these peanut hell pellets were essentially identical to the other two types.
>>
>>> 5. Figures 5 and 6 are identical - and the texts don't match with the figures.
>> Maybe 6 is the one in error - but who knows?
>>
>> Perhaps? The Figure label clearly states that it is supposed to be a cooking
>> power chart and it shows efficiency. That is a publisher's error. I have
>> requested the correct chart so I can share it here.
[RWL12: It is clear that Figure 5 is most unusual. I have no idea what to expect for #6. I think it will become clear soon that the fault is in the reported high energy density. Probably not even the fault of the first author. I doubt this is the first time someone has reported an energy density number inaccurately. It wouldn't surprise me that the right number was found and another used. What would greatly surprise me is if that number was correct.
>>
>>> 6. Several examples of not agreeing with other authors (including Jim Jetter -
>> maybe also "James"?) - but no explanations/rationales for the differences.
>>
>> So what? Why should articles agree with any particular author? The
>> researchers in this case described the purpose of the experiment, the
>> apparatus and the calculations used. The results are presented and discussed.
>> That is how scientific results are presented. Surely you don't expect them to
>> write an agreeable conclusion first and then conduct experiments hoping to
>> show it?
[RWL13: You didn't address my main point - no explanation or rationale in this paper for the huge differences. If correct, any such paper has an obligation to address them. This paper would not have been printed with what could be legal difficulties (from the peanut industry) if some thought and print went into the meaning of the results.
>>
>> Apart from your correctly identifying a printer's error, I believe we can safely
>> move on to the next topic.
[RWL14: I don't so believe. More coming from me on your later response to Paul today (I hope I don't have to do that).
I suggest that the wisest course for your team is to talk this over - with emphasis on other explanations (than hypothetical added oil) for this 30% high number.
Mistakes happen - they should be admitted. One presumably young, probably very bright, first author is the one who is going to be hurt, if a correction is not made soon.
Ron
>>
>> Regards
>> Crispin
>>
>
>
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